1. Field of the Invention
The present invention relates to an electrical junction box mounted on a vehicle or the like.
2. Description of the Related Art
Various electronic components such as a head lamp, a tail lamp, a starter motor and the like are generally mounted on a vehicle.
For supplying electricity to the various electronic components, junction block is disposed on a proper position of the vehicle. The junction block integrally includes many electric parts such as fuses and relays.
Incidentally, because the junction block may include a fuse, a relay, and a bus bar, the junction block is also referred to as a fuse block, a relay box, or an electrical junction box (for example, see Patent Document 1 and 2). Hereafter in this specification, the junction box is referred to as the electrical junction box.
The electrical junction box described in the Patent Document 1 and 2 includes a box main body, and a wiring block. The box main body is made of insulating synthetic resin, and formed in a box shape. A mounting part on which the electric parts such as a relay or a fuse are mounted, and a connecting part to which a connector of a wiring harness is connected are disposed on the box main body.
The box main body receives the wiring block. The wiring block includes a first bus bar to be connected to a battery as a first power source, a second bus bar to be connected to a generator as a second power source, a fuse to connect the first and second bus bars, and a connecting terminal.
The first and second bus bars are made of conductive plate metal. Each of the first and second bus bars includes a power source connecting part to be connected to the battery or the generator, and a terminal part to be positioned in the mounting part when the box main body receives the wiring block and to be connected to the electric parts such as the relay or the fuse.
The fuse connects the first and second bus bars at positions away from the power source connecting parts. A part of the connecting terminal is positioned in the mounting part and connected to the electric parts such as the relay or the fuse. The other part of the connecting terminal is positioned in the connecting part and connected to the connector of the wiring harness.
In the electrical junction box, the wiring block electrically connects the power sources, the electric parts, and electric wires of the wiring harness according to a predetermined pattern. Then, the electrical junction box supplies electricity to the electronic components connected to the wiring harness.
[Patent Document 1] Japanese Published Patent Application No. H10-241547
[Patent Document 2] Japanese Published Patent Application No. 2001-155618
Because the fuse connects the bus bars at positions away from the power source connecting parts in the electrical junction box, a large electric current flows through an almost full length of each bus bar. Therefore, for preventing the bus bars from heating, a width of each bus bar should be large through the full length thereof in a conventional electrical junction box. When the bus bar becomes wide through the full length thereof, the bus bar, namely, the wiring block becomes large, and the electrical junction box becomes large.
Accordingly, an object of the present invention is to provide an electrical junction box that can be small-sized.